Process for the preparation of a foamed product and products obtainable by this process

ABSTRACT

Foamed prodcuts based on an aqueous composition comprising an oxidised ferulyated polymer are stable both during storage and after freezing and subsequent storage. A process for preparing these products is provided.

FIELD OF THE INVENTION

[0001] The invention relates to a formulation and process for providingfoamed products which are freeze-thaw stable and also storage stable.

BACKGROUND OF THE INVENTION

[0002] The object of providing a freeze-thaw stable foam which is alsostorage stable has been addressed in the art.

[0003] U.S. Pat. No. 5,384,145 relates to a whipped topping based on anaqueous solution of whey protein isolate or concentrate which has a lowfat content of from 8% to 15% and has an overrun in excess of 250%,which is freeze-thaw stable and refrigerator stable for 21 days andshows good whippability.

[0004] However these compositions are not stable if oil is not includedin their composition. Furthermore the gas phase in these products isbelieved to be stabilised by non-covalent, physical bonding of wheyprotein on the gas/liquid interphase which is mainly due to proteindenaturation. These interactions are non covalent and hence do notprovide desired long term stability of the foam.

[0005] Furthermore foamed products based on egg white are widely known.However, egg white based foam is not freeze-thaw stable and not veryfirm.

[0006] WO-A-00/40098 discloses crosslinked pectin which is dried and assuch added to an ice cream formulation. The obtained products were foundto have a sol-like character meaning that it is like a dispersion ofgelled particles in a liquid, and did not maintain their shape uponstorage at room temperature for 30 minutes or more. Under these storageconditions the products collapsed.

[0007] Hence it is an object of the invention to provide a foamedproduct which is freeze-thaw stable, and shows a creamy, tasteless andsoft mouthfeel. Preferably these products are firm and they preferablyretain their shape during storage.

SUMMARY OF THE INVENTION

[0008] It has surprisingly been found that these features can befulfilled by a foamed composition comprising water and an oxidisedferulyolated compound prepared in a process wherein the oxidation iscarried out during or after foam formation.

[0009] Therefore the invention relates to a process for the preparationof a foamed product comprising the steps of:

[0010] a) providing a mixture of a liquid and a ferulyolated compound

[0011] b) incorporating a gas phase in this mixture

[0012] c) combining said mixture with an oxidant capable of oxidation ofthe ferulic acid groups in the ferulyolated compound, preferably underconditions wherein homogeneous distribution of the oxidant in the liquidis ensured.

[0013] In a further aspect the invention relates to a foamed productcomprising a dispersed gas phase and a liquid phase comprising anoxidised ferulyolated compound in an amount of from 1 to 20 wt % ontotal weight of the liquid phase, obtainable by the above process.

[0014] In a further aspect the invention relates to food productscomprising these foamed products.

DETAILED DESCRIPTION

[0015] For the purpose of the invention a foam is defined as anemulsion-like two phase system where gas bubbles are dispersed in a(sometimes relatively small) volume of liquid containing surface activemolecules, preferably macromolecules. A foam can for example be formedby whipping air into an aqueous composition comprising egg white.

[0016] The foams according to the invention optionally contain an oil,preferably a triglyceride oil, as a second dispersed phase. Theseproducts may show a more mousse like structure which is more dense thana common foam structure. However these products are also encompassed inthe invention.

[0017] Foams in the context of the invention differ from products with agel structure as these latter structures only comprise gas dissolved inthe liquid from which the gel is derived. The current foam productscomprise more gas than this level, which is determined merely by thesolubility of gas in the liquid from which the gel is derived.

[0018] Tasteless in the context of the invention means that the foamedproducts have a bland taste unless flavour compositions are added. Thisbland taste is desired as it enables use of the foams in any type ofproduct.

[0019] In the context of the invention, the terms “fat” and “oil” areused interchangeably. The term oil encompasses both triglyceride oilsand diglyceride oils.

[0020] For the purpose of the current invention, wt % is defined asweight percent on total weight of the liquid phase of the foamedproduct, unless otherwise is indicated. In this calculation, the liquidphase is considered to comprise all water soluble and water dispersibleingredients and all oil or ingredients that can be dissolved ordispersed therein.

[0021] The term oxidant is used to indicate an oxidising agent, whichcan be either a chemical oxidising agent or an enzyme. An enzyme can beused alone or in combination with a co-oxidant such as hydrogenperoxide.

[0022] The invention regards a process to prepare a foamed product, onthe basis of compounds containing ferulic acid groups. Care should betaken that the conditions are such that the desired specific volume andfirmness are reached. Especially the oxidation of the ferulic acid unitsshould be carefully controlled.

[0023] It is known that oxidation of a ferulyolated compound underquiescent conditions leads to the formation of a gel. Reference is madeto WO-A-96/03440 and WO-A-98/22513. Hence in the absence of any othermeasures, the blending of ferulyolated compound and an oxidant which issufficiently powerful to enable oxidation of the ferulic acid units,will lead to the formation of a gel.

[0024] It has surprisingly been found that if a gas phase isincorporated in a liquid comprising a ferulyolated compound, undersimultaneous oxidation and/or followed by oxidation, a foamed productresults which is freeze-thaw stable, storage stable and shows thedesired taste and mouth feel upon consumption.

[0025] Therefore in one aspect the invention relates to a process forthe preparation of a foamed product comprising the steps of:

[0026] a) providing a mixture of a liquid and a ferulyolated compound,

[0027] b) incorporating a gas phase in this mixture

[0028] c) combining said mixture with an oxidant capable of oxidation ofthe ferulic acid groups in the ferulyolated compound, preferably underconditions wherein homogeneous distribution of the oxidant in the liquidis ensured.

[0029] Without wishing to be bound by any theory, applicants believethat the oxidised ferulyolated compound acts as a surfactant and absorbsat the gas/liquid interface. In this way the ferulyolated compounds arebelieved to be responsible for the tendency of the liquid to foam and toimpart stability to the resulting foamed product. The cross linking ofthe ferulic acid units by oxidation is believed to fix the structure ofa dispersed gas phase in a matrix of ferulyolated compounds, therebyincreasing the stability of the foamed product, both in terms of storagestability and in terms of freeze-thaw stability.

[0030] The process according to the invention comprises in step (b) astep wherein a gas phase is incorporated into the mixture. This gasincorporation leads to the formation of a foam type structure.

[0031] The foam type structure is prone to decline and/or collapseunless step (c) is carried out. As explained above, it is believed thatin step (c) the foam structure is fixed by the covalent bonds whicharise from oxidation of the ferulic acid groups. Step (c) is theoxidation of ferulic acid groups. To prevent collapse of the formed foamstructure, it is desired that step (c) is carried out within a shorttime frame, preferably in the order of seconds to at most a few minutes.Suitable conditions to obtain this fast formation of an oxidisedstructure are exemplified below. Step (c) may be carried outsimultaneously with the incorporation of gas in step (b) or after thegas has been incorporated. Step (c) is preferably carried out after step(b). If the oxidation is carried out simultaneously, the oxidant ispreferably added towards the end of step (b) when at least part of thegas has been incorporated, preferably at least 50 vol % of the gas hasbeen incorporated.

[0032] Step (c) regards the combining of the preferably foamed mixturewith an oxidant to obtain oxidation of ferulic acid groups. Thiscombining may be carried out actively as an addition of oxidant to themixture of step (b). Alternatively the combining may result from theformation in situ of the oxidant in the mixture of step (b). In situgeneration of the oxidant may for example be mediated by the action ofglucose oxidase, forming hydrogenperoxide as a reaction product.Hydrogen peroxide is thus combined into the mixture.

[0033] The gas can be any gas, but is preferably selected from the groupcomprising air, nitrogen, carbon dioxide and ammonia gas.

[0034] The gas can be incorporated by any suitable method. Preferablythe gas phase is incorporated by a method selected from the groupcomprising subjecting the mixture to high shear treatment, addition of aleavening system under conditions where leavening takes place, additionof an enzymatic system which leads to gas formation.

[0035] If gas is incorporated by a shear treatment, said shear treatmentin step (b) is preferably a high shear treatment. For the purpose of theinvention shear is defined as a strain resulting from applied forcesthat cause or tend to cause contiguous parts of a body to sliderelatively to each other in a direction parallel to their plane ofcontact.

[0036] It has been found that gentle shaking of a product does not leadto formation of a foam, nor does gentle mixing of the two componentswith a fork. Use of a home mixer at the lowest speed may lead to theformation of a foam but this will have a small overrun only.

[0037] For the purpose of the invention overrun is defined as theincrease in volume of a product over the volume of the mix due to theincorporation of gas. For further information on overrun reference ismade to Marshall et al 1996 in “Ice Cream”.

[0038] Examples of suitable apparatus to impart shear are a turrax™, aHobart™ at high speed, and a scraped surface heat exchanger. Furtherguidance on high shear treatment is provided in the examples.

[0039] Preferably these apparatus are used at at least half of theirmaximum stirring speed to obtain a foamed product.

[0040] Preferably the shear treatment in step (b) continues for sometime to increase the specific volume of the liquid to produce a foam.Preferably the shear is applied until the specific volume of the foamreaches its maximum value. The total amount of time during which shearis applied is preferably from 1 second to several minutes, morepreferred from 2 seconds up to 5 minutes, most preferred from 5 secondsup to 1 minute. As a guideline it is preferred that the shear treatmentis stopped once the foam has been formed and does not increase visiblyin volume anymore. This can be determined quantitatively bydetermination of the specific volume versus time. Generally a largervolume of starting liquid requires a longer shear treatment before themaximum specific volume for the system is obtained. A skilled personwill understand that the time during which shear is applied, amongothers also depends on the shear rate.

[0041] According to another embodiment, gas is incorporated by use of aleavening salt. Suitable leavening systems are for example described inCereal Foods World, 41, pages 114-116, 1996 and include yeastfermentation or chemical leavening systems.

[0042] Preferably the leavening agent included in the leavening systemis selected from the group of sodium bicarbonate, potassium bicarbonate,ammonium bicarbonate and disodiumpyrophosphate.

[0043] Alternatively gas is incorporated by addition of an enzymaticsystem generating a gas. A suitable example of such a system is thecombination of a catalase and hydrogen peroxide as substrate, which willlead to the formation of oxygen gas.

[0044] The amount of gas that is included in a volume of liquiddetermines the specific volume of a foamed product. The foamed productsaccording to the invention preferably show a specific volume betweenabout 0.01 to 0.9 g/ml, more preferred 0.1 to 0.7 g/ml. The method todetermine specific volume is described in the examples.

[0045] Shear is preferably applied during mixing of the ferulyolatedcompound and the oxidant in step (c). Preferably the oxidant is added tothe gas phase containing mixture.

[0046] The shear applied in this step may be low or high shear as longas the shear treatment ensures that the oxidant is preferablydistributed homogeneously in the liquid. If the distribution is nothomogeneous, only local oxidation may result and other parts of theliquid may not be oxidised and hence will not structure the foam.

[0047] After the incorporation of a gas in step (b) and after blendingof the oxidant, preferably the foamed product is left to stand for sometime, preferably 10 seconds to 1 minute to ensure that oxidation of theferulic acid groups can take place to fix the foam that has been formedin step (b).

[0048] In a preferred process, the temperature during mixing in step (a)is between 10 and 40° C.

[0049] The temperature in step (b) can be any suitable temperature. Atemperature between −20 and 40° C., preferably from 4 to 20° C. ispreferred.

[0050] The foamed product is preferably stored at a temperature below25° C., more preferred from −20 to 25° C.

[0051] Storage at increased temperature of about 50 to 90° C. ispossible but was found to lead to a dried structure. After such a dryingtreatment at increased temperature, a brittle foam results. Thisstructure resembles the structure of a meringue. In a further aspect theprocess includes this drying step.

[0052] The oxidation may be accomplished by the action of a powerfulchemical oxidant such as potassium periodate, potassium permanganate, orpotassium ferricyanide.

[0053] Alternatively the oxidation can be accomplished by use of anoxidising enzyme such as a peroxidase, a polyphenol oxidase e.g.catechol oxidase, tyrosinase, or a laccase.

[0054] Peroxidases can be divided into those originating from plants,fungi or bacteria and those originating from a mammalian source such asmyeloperoxidase and lactoperoxidase (LPO).

[0055] Laccases are obtainable from a variety of microbial sourcesnotably bacteria and fungi (including filamentous fungi and yeasts), andsuitable examples of laccases include those obtainable from strains ofAspergillus, Neurospora (e.g. N. crassa), Prodospora, Botrytis,Collybia, Fomes, Lentinus, Pleurotus, Trametes [some species/strains ofwhich are known by various names and/or have previously been classifiedwithin other genera], Polyporus, Rhizoctonia, Coprinus, Psatyrella,Myceliophtora, Schytalidium, Phlebia or Coriolus.

[0056] Preferred enzymes are selected from the group comprisinghorseradish peroxidase, soy bean peroxidase, Arthromyces ramosusperoxidase and laccases that show a redox potential of preferably morethan 550 mV as described in E. Solomon et al, Chem Rev, 1996, p2563-2605.

[0057] The extent of oxidation of the ferulyolated compound can bemeasured by spectrophotometric determination of the absorbance at 375nm. Absorption at this wavelength is characteristic for an oxidisedferulic acid group.

[0058] In case a chemical oxidant is applied, the oxidant is preferablyadded in the form of a diluted aqueous solution.

[0059] In case an enzymatic oxidising system is applied, the enzyme ispreferably added in the form of a solution or a dispersion in an aqueousbuffer system. The enzymes cited above are suitable enzymes. Someenzymes, such as peroxidases require the presence of a co-oxidant suchas hydrogen peroxide for their activity. The co-oxidant is preferablyadded separately from the enzyme that requires it's presence.

[0060] The amount of enzyme added is expressed in terms of activityunits. Preferably enzyme is present in excess. The amount of enzymeadded is preferably such that fast gelation occurs to immediately fixthe foam structure created in step (b). For a peroxidase the amount ofenzyme added is preferably from 50 to 10.000 units ABTS activity per mlof liquid.

[0061] The gas incorporation in step (b) and oxidation in step (c) canbe carried out at any temperature, e.g. between −20° C. and 40° C.,preferably from 20 to 40° C. If the oxidation is carried outenzymatically, the temperature during step (b)-(c) is preferably from 20to 40° C. However also lower temperature are possible provided theenzyme shows activity at this temperature. Therefore most preferred thetemperature is around the temperature at which the enzyme shows maximumactivity.

[0062] Optionally oil or fat is included in the foam product. The oilsand fats as listed above can suitably be included.

[0063] The oil or fat is preferably added between step (a) and (b) orduring the incorporation of gas in step (b).

[0064] It is preferred that the oil or fat is added to the water phaseto form a water continuous liquid instead of the reversed order wherebya fat continuous system is formed.

[0065] In a further aspect the invention relates to a foamed productcomprising a dispersed gas phase and a liquid phase comprising anoxidised ferulyolated compound in an amount of from 1 to 20 wt % ontotal weight of the liquid phase, obtainable by the above process.

[0066] The preferred ingredients/liquid composition as outlined belowequally apply to the foamed products as prepared according to the aboveprocess.

[0067] The foamed products according to the invention are freeze-thawstable. In the context of the invention this implies that after storageat at least −20° C. for a period of at least 2 hours, and subsequentthawing at room temperature (about 25° C.), the products arecharacterized by a specific volume which is 70 to 100% of the specificvolume of the foamed product before it was stored at at least −20° C.

[0068] The foamed products according to the invention are also storagestable. This means that the foamed product when stored at a temperatureof from 4 to 25° C. for at least 7 days shows a specific volume which isat least 70 to 100% of the specific volume before storage. Furthermorestorage stable products preferably do not show an off flavour uponstorage. Flavour/taste and colour characteristics are determined by apanel test.

[0069] In a further aspect the invention relates to a foamed productcomprising a dispersed gas phase and a liquid phase comprising anoxidised ferulyolated compound in an amount of from 1 wt % to 20 wt % ontotal weight of the liquid phase, said product being stable at ambienttemperature.

[0070] A first insight in freeze-thaw stability and storage stability offoams can be obtained by visual inspection of the thawed products. Foamswhich collapse or show a strong volume decline and/or substantial waterrelease are not stable in the context of the invention.

[0071] The foamed products according to the invention are firm whichmeans they show a hardness value of at least 0.5 g, more preferred from0.5 to 25 g, even more preferred from 8 g to 24 g, at room temperature(about 25° C.) under the measurement conditions indicated in theexamples.

[0072] Preferably freeze-thaw stable foams show a difference in hardnessvalue of at most 20% compared to the hardness value before they werefrozen and thawed under the conditions specified above.

[0073] According to a further aspect stable products (both with respectto storage stability and freeze-thaw stability) do not show waterrelease after the respective treatments. Water release is often seen onfoam type products or emulsions and is referred to as syneresis.

[0074] The method to determine water release is described in theexamples. Preferred products show a water release of less than 0.2 ml/gdetermined by the method according to the examples.

[0075] More preferably the foams according to the invention showsubstantially no water release after storage or after a freeze-thawtreatment as specified above.

[0076] Examples of foamed products are whipped toppings, whipped cream,foamed shaving cream.

[0077] The foamed product comprises an oxidised ferulyolated compound inthe liquid phase. Ferulic acid groups(4-hydroxy-3-methoxy-cinnamyl—groups) are known to be capable ofcrosslinking in the presence of certain oxidants (e.g. Oosterveld et al;oxidative crosslinking of pectic polysaccharides from sugar beet pulp,Carbohydrate research 328; 199-207, 2000). In the oxidation process anew covalent bond is formed between two individual ferulic acid groups.

[0078] The compound comprising oxidised ferulyolated groups ispreferably a polymer, more preferred a polysaccharide. Examples ofsuitable polymers include pectin, arabinan, galactan, cellulosederivatives, galactomannans such as guar gum, locust bean gum, starchesor other polymers comprising hydroxyl groups which can be esterified toa ferulic acid group.

[0079] The polymers comprising ferulic acid groups can be naturallyoccurring or synthesised polymers. Examples of naturally occurringpolymers with ferulic acid groups are sugar beet pectin andarabinoxylanes isolated from cereals.

[0080] Synthetic processes to prepare polymers with ferulic acid groupsgenerally include esterification of ferulic acid to a free hydroxylgroup situated on the polymer backbone or on a sugar substituent.

[0081] In a highly preferred embodiment, the foamed product comprises anoxidised pectin, even more preferred oxidised sugar beet pectin. Theprincipal building units of pectin are smooth homogalacturonic regionsand rhamnified hairy regions in which most neutral sugars are located.Arabinose is the predominant neutral sugar. Galactose is present inrhamnogalacturonan. 50-55% of the ferulic acid groups are linked toarabinose units and about 45-50% of the ferulic acid groups are linkedto galactose residues.

[0082] Preferably 15 to 80% of all ferulic acid groups are oxidised inthe final foamed product.

[0083] It is preferred that the majority of ferulic acid groups is notoxidised before gas is incorporated in step (b). More preferred beforestep (b) at most 10% of all ferulic acid groups are oxidised.

[0084] The amount of oxidised ferulyolated compound in the liquid phaseof the foamed product is from 1 to 20 wt %. Lower amounts were found notto provide sufficient firmness and storage stability was unsatisfactory.Higher amounts often do not dissolve at a satisfactory level and maylead to inclusion of the oxidant by oxidised polymers. This mayinactivate the oxidant and may lead to phase separation.

[0085] Preferably the amount of oxidised ferulyolated compound is from 1to 10 wt %, more preferred 1 to 4 wt %, even more preferred from 2 to 4wt % on total liquid phase.

[0086] The liquid phase can be any liquid phase, but the presence of atleast some water is required.

[0087] In a highly preferred embodiment, the liquid phase compriseswater in an amount of at least 20 wt % on total weight of the liquidphase.

[0088] Examples of liquid phases which fulfil this requirement are milk,cream, juices and certain oil in water and water in oil emulsions.

[0089] These liquid phases are preferred for the product according tothe invention.

[0090] Optionally the liquid phase comprises an organic solvent such asethanol.

[0091] Although the protein based foams as described in the prior artwere as such found to be unstable upon freezing and thawing, the currentproducts may comprise some protein. Protein may serve to improve theirnutritional value, their taste and appearance and foam volume especiallyif the foam is prepared at relatively low shear.

[0092] However care should be taken that the amount of protein is nottoo high, which was found to lead to products which do not show thedesired freeze-thaw stability.

[0093] Therefore the foamed product preferably comprises protein in anamount from 0.1 to 15 wt %, more preferred from 1 to 10 wt %, even morepreferred from 2 to 5 wt %, on total weight of the liquid phase.

[0094] Suitable proteins include whey protein, egg white protein,casein, other milk protein, soy protein, potato protein, rice protein,shea protein, maize protein, barley protein or a combination thereof.

[0095] In a highly preferred embodiment the products according to theinvention comprise a protein in an amount from 1 to 5 wt % and aferulyolated pectin in an amount from 1 to 4 wt %.

[0096] It is well known that fat present in an aqueous egg whitecomposition prevents the whippability of the composition to a greatextent. It has surprisingly been found that the current foams are stableand show the desired specific volume, even in the presence of oil orfat. It has been found that amounts of fat or oil up to 60 wt % on theliquid phase volume are tolerable and do not severely reduce the foamfirmness or its stability. Compared to a foam based only on ferulyolatedcompound, without fat or oil, the compositions that contain oil or fatshow a more creamy, mousse-like structure with less overrun. Forproducts comprising oil or fat the specific volume is preferably from0.01 to 0.9 g/ml, preferably 0.1 to 0.9 g/ml.

[0097] The oil or fat is preferably selected from the group comprisingsunflower oil, coconut oil, butter fat, rapeseed oil, olive oil, peanutoil or oils extracted from plant or flower material such as rose oil,and combinations thereof. Also fractionated oils are encompassed in theinvention.

[0098] The foamed product may optionally comprise further ingredientssuch as salt, flavour components, colourants, emulsifiers, acidifyingagents, (co)-oxidants such as hydrogen peroxide, and the like. Ifparticulate ingredients such as fruit pieces or nuts are added, it ispreferred that these are added shortly after the desired specific volumehas been reached and while oxidation is at least ongoing. This ispreferred because the particulate ingredients are then likely to beenclosed in the oxidised crosslinked network, which improves thestability of the final foamed product and reduces the tendency of theparticulate ingredients to precipitate on the bottom of a jar containingthe foamed product.

[0099] In a further aspect the invention relates to a food productcomprising a foamed product according to the invention. Examples of foodproducts which suitably may incorporate the foamed product include icecream, margarine, table spreads, butter, desserts, and yoghurt.

[0100] The invention is especially suitable for ice cream, milk ices andwater ice products. Water ice, milk ice and ice cream will be referredto as frozen confection hereafter. Such products and processes toprepare these are for example disclosed in “Ice Cream” by R. T. Marshall& W. S. Arbuckle, 5^(th) Edition, 1996, Chapman & Hall, New York.

[0101] A frozen confection is a foamed, sweet product containing a largeamount of ice. Frozen confections generally comprise sugars andsweeteners (such as sucrose and glucose), water and optionallyingredients selected from the group comprising protein, fat, thickeners,emulsifiers and stabilisers. Furthermore taste and flavour components orpreservatives are optionally included.

[0102] Water ice and milk ice are generally fat-free whereas ice creampreferably comprises from 2 to 20% fat. The overrun of frozenconfections is preferably from 30 to 150%. The preferred overrun amongothers depends on the type of ice product. The overrun for water ice isgenerally lower than for ice cream.

[0103] In this preferred aspect a process is provided for preparing afrozen confection wherein

[0104] a) a mixture of ingredients of the frozen confection and aferulyolated compound in water is prepared at a preferred temperature offrom 15 to 60° C.

[0105] b) a gas phase is incorporated in this mixture

[0106] c) the mixture is mixed with an oxidant capable of oxidation ofthe ferulic acid groups in the ferulyolated compound, preferably underconditions wherein homogeneous distribution of the oxidant in the liquidis ensured

[0107] d) the foam which results from step (c) is frozen at atemperature below minus 4° C., preferably from −50 to −10° C.

[0108] The mixture of step (a) is preferably a homogeneous mixture ofthe ingredients in the frozen confection. The ingredients are describedbelow.

[0109] In step (c) ferulic acid groups are linked by oxidation. This iscarried out simultaneously with gas incorporation or more preferredafter incorporation of gas in step (b).

[0110] Preferably the oxidation in step (c) is continued for some time,preferably in the order of 1-10 minutes, to allow the product to reachmaximum stability. Hence it is preferred that freezing is not doneimmediately after step (c) but after the foamed mixture has been allowedto stand for at least about 1 minute.

[0111] Optionally a homogenisation and/or pasteurisation and/orsterilisation step is included before step (b).

[0112] The temperature during step (b) and (c) can be any suitabletemperature. A temperature from (minus) −20° C. to +15° C., preferablyfrom −15° C. to +5° C. is preferred. Optionally the product is alreadypartly frozen before step (d).

[0113] The preferred characteristics of the foamed product describedabove equally apply to the process for preparing a frozen confection.

[0114] In a further aspect the invention relates to a frozen confection,preferably ice cream obtainable by this process.

[0115] The preferred ferulyolated compound is (sugar beet) pectin,preferably in an amount of from 0.8 to 5 wt %, more preferred from 1 to4 wt % on total weight of the frozen confection.

[0116] Ice cream preferably comprises about 2 to 7 wt % protein whichare usually added as part of whey powder or skim milk powder. Commonsweeteners that are optionally included are preferably selected from thegroup comprising sucrose, glucose, lactose, corn syrups or a combinationthereof.

[0117] Stabilisers are preferably selected from the group comprisingguar gum, locust been gum, carrageenan, starch, gelatin or a combinationthereof. Preferred amount is from 0.1 to 1 wt % on product.

[0118] Preferred emulsifiers are selected from the group comprisingsaturated monoglycerides, saturated diglycerides of fatty acids,polyglycerol esters, sorbitan esters, stearoyl lactylate, lactic acidesters, citric acid esters, acetyllated monoglyceride, diacetyl tartaricacid esters, polyoxyethylene sorbitan esters, lecithin, egg yolk, or acombination thereof. Preferred amount is from 0.05 to 0.5 wt % onproduct.

[0119] Optionally the frozen confection comprises colour or flavourcomponents. A well known flavour component for ice cream is for examplevanillin. Care should be taken that vanillin is preferably added afterthe oxidation in step (c) has been completed because of the structuralsimilarity of ferulic acid and vanillin. Addition of vanillin beforeoxidation may perturb the oxidation reaction. Alternatively the vanillinlevel is sufficiently low compared to the amount of ferulyolatedcompound such that the oxidation reaction is not disturbed. It wasfurther found that the presence of fat in which vanillin easilydissolves, may reduce any negative influence of vanillin on theoxidation of ferulic acid residues.

[0120] The stability of these ice confections is preferably determinedby a so called meltdown test which is described in the examples.

[0121] In an alternative embodiment, the invention relates to creamy orpastey products comprising the foamed product. Examples of such productsinclude shaving cream and skin cream.

[0122] The invention is illustrated by the following examples.

EXAMPLES General Techniques That Were Applied

[0123] 1. Measurement of Hardness

[0124] Apparatus used: Texture Analyser model LFRA 1000g/100 g from CNCFarnell. Unit 1 Manor place Manor Way, Boreham Woods, Herts, UK.

[0125] Probe used: probe made of synthetic material,

[0126] probe size: diameter 25 mm, height 35 mm.

[0127] Settings of the Texture analyser:

[0128] Penetration speed: 2 mm/sec

[0129] Distance: 10 mm

[0130] The hardness value is determined in grams.

[0131] The temperature is 25° C.

[0132] 2. Determination of Specific Volume (S.V.)

[0133] The specific volume of the foamed product was measured by fillinga calibrated cup with known volume and weight and leveling the top. Theweight of the filled cup was measured. SV is the ratio between thevolume of the foamed product in the cup and the weight of the foamedproduct in the cup expressed as g/ml.

[0134] 3. Determination of Water Release

[0135] Calibrated 50 ml tubes were completely filled with foam. Waterrelease (water layer on bottom of tube) was determined. The weight ofthe foam was determined by weighing the empty and the filled tube. Waterrelease is expressed as ml water released per gram of foam.

[0136] 4. Activity Assay

[0137] Add 100 μl 20 mM ABTS(2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) stocksolution made in indicated buffer) to 880 μl 25 mM phosphate buffer, pH6.0. Incubate for 5′ at 30° C. Add 10 μl 100 mM hydrogen peroxide. Startthe reaction by addition of 10 μl enzyme (diluted in such a way that alinear curve could be measured). Measure the formation of ABTS radicalat 414 nm using a spectrophotometer.

[0138] Specific activity is defined as: μmol ABTS oxidised per minuteper mg protein at pH 6.

Example 1-2

[0139] Materials:

[0140] 12.5 wt % egg white solution (prepared from High-Whip powder, vanEnthoven) in water

[0141] 4 wt % sugar beet pectin solution in water

[0142] 100 mM hydrogen peroxide

[0143] 0.106 mg/ml (specific activity=6.10 exp 5 units per mg at pH 6)ARP (peroxidase from Arthromyces Ramosus.

[0144] Horseradish peroxidase (HRP) stock solution 0.6 mg/ml specificactivity 3.2 exp 4 units per mg.

[0145] Experiments were performed in glass 10 ml tubes. An ultra-turraxwas used at the highest speed. All the components, except for theenzyme, were mixed and briefly (1-2 seconds) submitted to high shearwith a Turrax™ mixer at the highest speed. Then the enzyme was added(during shear). When the foam had been formed (after a few seconds), theshear treatment was stopped so that the enzyme could fix the foam. TABLE1 composition examples 1-2 12.5% egg 100 mM 4% pectin white hydrogenSample Water solution solution peroxide ARP no. (μl) (μl) (μl) (μl) (μl)1 1000 1000 — 20 40 2  680 1000 320 20 40

[0146] Results Examples 1-2: TABLE 2 Freeze- sample thaw Visual Storagestability no. stable characteristics at 20° C. 1 yes White foam good 2yes White foam good

Example 3-7

[0147] Materials:

[0148] Sunflower oil

[0149] 4% sugar beet pectin solution, sugar beet GENU pectin type BETAfrom CP Kelco (Denmark) product info number 1005-19, batch no 02995.

[0150] 100 mM hydrogen peroxide

[0151] 0.106 mg/ml (2.10⁴ ABTS units at pH 6) ARP (peroxidase fromArthromyces ramosus stock solution 0.106 mg/ml, activity 2.10e4 ABTSunits per ml).

[0152] Process

[0153] Oil-in-water: pectin, water and hydrogen peroxide were mixed andthen submitted to high shear with a Turrax™ mixer at the highest speed.During shear treatment the oil was added slowly. When all the oil hadbeen added, ARP was added.

[0154] Water-in-oil: pectin, water and hydrogen peroxide were mixedseparately (water phase). The oil phase was submitted to high shear witha Turrax™ mixer at the highest speed and the water phase was addedslowly. When the complete water phase was added, ARP was added to theemulsion.

[0155] Experiments were performed in small glass jars (˜10 ml). Theultra-turrax™ (Janke & Kunkel, IBA labortechniek) T25, 24000 rpm as usedat the highest speed. TABLE 3 100 mM 4% sunflower hydrogen Sample waterpectin oil peroxide ARP HRP no. (μl) (μl) (μl) (μl) (μl) (μl) 3 16002000  400 40 80 — 4 1600 2000  400 40 — 14 5 1200 2000  800 40 80 — 6 400 2000 1600 40 80 — 7  400 2000 1600 40 80 —

[0156] Example number 7 resulted in a water in oil emulsion, the otherswere oil in water emulsions.

[0157] Results: TABLE 4 Visible Stability sample % characteristics(after 3 days at no. oil of product 20° C.) 3 10 white, firm littlewater release 4 10 white, firm see 3 5 20 white, firm little waterrelease but less than in 3 and 4 6 40 white, firm no oil release 7 40white, firm no oil release

[0158] The firm white structure that was formed looked creamy, wastasteless and felt soft in the mouth.

Examples 8-9

[0159] The procedure of example 1 and 2 was used, with the ingredientcomposition as outlined below. In stead of an ultraturrax, a Hobart™mixer at maximum speed (3) was used for foam formation before oxidation.The Hobart™ mixer used was a model N5D at maximum speed (1425 rpm)equipped with a wired whisk (B flat beater). ARP was added immediatelywhen a foam had been formed after which mixing was continued for about15 seconds. The time of shear treatment in the Hobart™ mixer was 5minutes for example 8 and 9. TABLE 5 composition examples 8 and 9 12.5%egg 1 M 4% pectin white hydrogen Sample Water solution solution peroxideARP no. (ml) (ml) (ml) (ml) (ml) 8 125 125 — 0.25 5 9  85 125 40 0.25 5

Results Examples 8 and 9

[0160] TABLE 6 Water Freeze- hardness release sample thaw SV beforevalue at Visual after 24 no. stable thawing 25 ° C. characteristicshours 8 yes 0.81 g/ml 25.5 White 0.13 foam ml/g 9 yes 0.14 g/ml 14 White0.16 foam ml/g

[0161] It was concluded that in the presence of some egg white, a higherspecific volume can be obtained. However these products are less stableand less firm although they still show the desired firmness andstability.

Example 10

[0162] 0.2 g sodiumbicarbonate and 0.26g disodiumpyrophosphate wereadded to 10 ml 4% sugar beet pectin (the same as described in ex. 3-7)solution under stirring with a magnetic stirrer bar. Immediately afterthe salts were added, 80 μl polyporus pincitus laccase was added (6.6mg/ml, 22 Units/mg) to obtain oxidising of the ferulic acid groups ofpectin.

[0163] The resulting product was a stable foam.

Comparative Examples (Not According to the Invention) ComparativeExamples A-C Composition

[0164] TABLE 7 12.5% 100 mM egg hydrogen Sample Water 4% pectin whiteperoxide ARP no. (μl) (μl) (μl) (μl) (μl) A — — 2000 — — B 1680 —  320 —— C  680 1000  320 — —

Comparative Example A-C Results

[0165] TABLE 8 Freeze- Storage sample thaw stability no. stable at 20°C. A no Instable B No Instable C No instable

[0166] After 5 minutes at room temperature in samples A, B, C, a liquidlayer was formed under the foam. After about 30 minutes this effect hadslightly increased.

[0167] Therefore it is concluded that the lack of fixing of the foamstructure by oxidation, leads to instable products, not fulfilling therequirements of the invention.

Comparative Example D-F

[0168] TABLE 9 100 mM 4% sunflower hydrogen Sample water pectin oilperoxide ARP HRP no. (μl) (μl) (μl) (μl) (μl (μl) D 1600 2000  400 40 —— E 1200 2000  800 40 — — — 2000 2000 40 80 —

Results Comparative Example D-F

[0169] TABLE 10 Stability sample % % (after 3 no. pectin oil resultdays) D 2% 10 white, fluid E 2% 20 white, complete fluid phaseseparation F 2% 50 white, complete fluid phase separation

[0170] On the basis of these results it was concluded that high amountsof oil outside the claimed range, leads to instable products.Furthermore if no oxidant is present, there is either no foam formationor the formed foam is instable.

Comparative Example G, H, I

[0171] The procedure of comparative example A and B was used, with theingredient composition as outlined below. In stead of an ultraturrax, aHobart mixer at maximum speed (3) was used for foam formation beforeoxidation. TABLE 11 composition comparative examples G, H, I 12.5% egg 1M 4% pectin white hydrogen Sample Water solution solution peroxide no.(ml) (ml) (ml) (ml) G 210 125 — 0.25 H  85 125  40 — I — — 125 —

Results Comparative Examples G, H, I

[0172] TABLE 12 Water hardness release Freeze- value at after 24 samplethaw SV before 25° C. hours no. stable thawing (g) (ml/g) G No  0.11g/ml 26.5 0.93 H No 0.088 g/ml 15.5 0.82 I no 0.073 7 0.95

[0173] On the basis of these experiments it was concluded that theabsence of oxidant or the use of a not powerful oxidant such ashydrogenperoxide as such, leads to the formation of products which arenot freeze-thaw stable.

Example 11

[0174] The formulation shown in Table 13 was prepared. This base mix wasthen aerated (a) with the cross-linking of the pectin and (b) withoutthe cross-linking of the pectin (comparative example). The aerated mixeswere then frozen, and the improved temperature stability of the icecream products was demonstrated using a meltdown test. TABLE 13Formulation of the base mix Ingredient wt. % Skimmed Milk Powder(Sunsheaf, Ca. 35% protein) 7.4 Whey Powder (“Espiron 300”, DMV Int.,Ca. 30% 2.6 protein) Sucrose (Tate and Lyle) 15.6 Coconut Oil (“HARDKO”,Loders Croklaan) 12 Saturated Mono-/di- glycerides (“Admul MG40-04, 0.39Quest Int.) Vanilla Flavour (Quest Int.) 0.05 β-carotene (Roche) 0.01Sugar Beet Pectin (“Genu ® Beta pectin”, CP 2 Kelco) Water to 100%

Mix Preparation

[0175] The pre-mix is the unhomogenised, unpasteurised mixture ofingredients. 40 kg of pre-mix was made up by adding milk powders, sugarsand stabiliser to water at 55° C. In these formulations, emulsifierswere dissolved in molten fat before the mixture was blended with theaqueous ingredients.

[0176] The pre-mix was then heated to 82° C. with a plate heatexchanger, followed by homogenisation with a single stage valvehomogeniser (APV Crepaco Homogeniser F-8831 3DDL) at 140 bar pressure.The pre-mix was then pasteurized at this temperature for 25 seconds. Themix was cooled to 5° C. with a plate heat exchanger, and then collectedin a 50 kg stainless steel churn, and stored at 2° C.

Aeration of the Mix

[0177] From this base mix (formulation shown in Table 13), three aeratedmixes were produced. 4 kg batches of mix were aerated using a Hobartmixer set at speed setting 3. The mixes were all aerated toapproximately 100% overrun. To achieve 100% OR took approximately 8minutes of continuous whipping. Cross-linking agents were added asfollows:

[0178] Mix 1. With no cross-linking of the pectin during aeration (i.e.no addition of enzyme and hydrogen peroxide).

[0179] Mix 2. Where the pectin was cross-linked during aeration by theaddition of 0.175 wt. % Biobake Wheat (peroxidase) to the mix, followedby 0.2% (w/v) of 1 mol dm⁻³ hydrogen peroxide before aeration began.

[0180] Mix 3. Where the pectin was cross-linked after aeration by theaddition of of 0.175 wt. % Biobake Wheat (peroxidase) to the mix,followed by 0.2% (w/v) of 1 mol dm⁻³ hydrogen peroxide to the aeratedmix. Further mixing (20 s) was used to incorporate the ingredientsevenly.

[0181] (Biobake Wheat is an enzyme preparation from Quest Internationalthat contains soy bean peroxidase with an activity of 2000 units per g.)

[0182] Following aeration, the products were collected in 500 mLwax-coated cartons, and frozen at −25° C.

Experimental Procedure for Meltdown Tests

[0183] Tests were performed on a stainless steel wire mesh grid having asize of 25×25 cm, with 5 mm holes, 1 mm thick wire. Underneath the gridwas disposed a collecting vessel (of large enough volume to collect theentire sample tested) and balances for weighing the material collectedin the vessel. The balances are connected to a data logging system torecord the mass collected The grids were placed in a meltdown cabinetset at a constant temperature environment 37° C. and which was capableof holding up to 12 of these grids simultaneously. Trays of water wereplaced within the cabinet to increase humidity and prevent any samplesplaced therein from drying.

[0184] Before placement in the cabinet the ice cream samples wereequilibrated in a freezer at −25° C., and then weighed on a zeroedbalance. They were then placed on the mesh grid and were arrangedrandomly over the available positions in the meltdown cabinet. Once allsamples were in place, the data logging system measured the amount ofcollected material every minute over a 240 minute time period.

[0185] From the mass of the sample collected over this period, thepercentage mass loss of the samples is calculated using the followingformula.${\% \quad {MassLoss}} = {\frac{M_{t} - M_{0}}{F} \times 100}$

[0186] wherein;

[0187] M_(t)=mass recorded (gram) at time t minute

[0188] M₀=mass recorded (gram) at start of analysis, t=0 minute

[0189] F=Initial mass of product (gram)

[0190] The % mass loss (%ML) for two samples of each formulation wasaveraged. From these data, the initiation time (t^(4%)) for each sampleof formulation was calculated. This is defined by the time that elapsesbefore a percentage mass loss of 4% is achieved.

Results of the Meltdown Test

[0191] Initiation times for the mixes, and mass loss after 120 and 240minutes are summarised in Table 14. TABLE 14 Initiation time and massloss data for the three ice cream products. Initiation Mass loss time(t^(4%))/ Mass loss after after 240 Mix minute 120 minutes/% minutes/% 112 93 92 2 — 0 0 3 — 0 0

[0192] From these data, it is concluded that the cross-linking of thepectin (both during and after aeration) leads to a significantly morestable foam compared to the same formulation containing pectin which isnot cross-linked. Mix 1, where no cross-linking of the pectin occurs,shows rapid meltdown behaviour. Mixes 2 and 3, where cross-linking ofthe pectin does take place, show no appreciable meltdown whatsoever overthe 240 minute time period.

[0193] The presence of a low amount of vanillin, in combination with theoil, did not negatively influence the final product.

1. Process for the preparation of a foamed product comprising the stepsof: a) providing a mixture of a liquid and a ferulyolated compound b)incorporating a gas phase in this mixture c) combining said mixture withan oxidant capable of oxidation of the ferulic acid groups in theferulyolated compound, preferably under conditions wherein homogeneousdistribution of the oxidant in the liquid is ensured.
 2. Processaccording to claim 1 wherein the gas phase is incorporated by a methodselected from the group comprising subjecting the mixture to high sheartreatment, addition of a leavening system under conditions whereleavening takes place, addition of an enzymatic system which leads togas formation.
 3. Process according to any of claims 1-2 wherein theoxidant is an enzyme or enzymatic system.
 4. Process according to any ofclaims 1-3 wherein the temperature in step (b)-(c) is between −20° C.and 40° C., preferably 4 to 20° C.
 5. Process according to any of claims1-4, which additionally comprises a drying step.
 6. Foamed productobtainable by the process according to any of claims 1-4 said productcomprising a dispersed gas phase and a liquid phase comprising anoxidised ferulyolated compound in an amount of from 1 wt % to 20 wt % ontotal weight of the liquid phase.
 7. Foamed product according to claim 6wherein the liquid phase comprises water in an amount of at least 20 wt% on total weight of the liquid phase.
 8. Foamed product according toany of claims 6-7 wherein the liquid phase is selected from the groupcomprising water, milk, cream, juices, oil in water and water in oilemulsions.
 9. Foamed product according to any of claims 6-8 whichcomprises protein in an amount from 0.1 to 20 wt % on total weight ofthe liquid phase.
 10. Foamed product according to any of claims 6-9which comprises up to 60 wt % oil on total weight of the liquid phase.11. Foamed product according to any of claims 6-10 having a specificvolume of from 0.01 to 0.9 g/ml.
 12. Foamed product according to any ofclaims 6-11 wherein the ferulyolated compound is a pectin.
 13. Foamedproduct according to claim 12 wherein the ferulyolated compound is sugarbeet pectin.
 14. Foamed product obtainable by the process according toclaim
 5. 15. Food product comprising a foamed product according to anyof claims 6-14.
 16. Shaving cream comprising a foamed product accordingto any of claims 6-14.
 17. A process for preparing a frozen confectionwherein a) a mixture of ingredients of the frozen confection and aferulyolated compound in water is prepared at a preferred temperature offrom 15 to 60° C. b) a gas phase is incorporated in this mixture c) themixture is mixed with an oxidant capable of oxidation of the ferulicacid groups in the ferulyolated compound, preferably under conditionswherein homogeneous distribution of the oxidant in the liquid is ensuredd) the foam which results from step (c) is frozen at a temperature belowminus 4° C., preferably from −50 to −10° C.
 18. Frozen confectionobtainable by the process according to claim 17.